How does the burning of methane release chemical energy that can be put to work

An electron loses potential energy when it shifts from a less electronegative atom to a more electronegative one, just as a ball loses potential energy when it rolls downhill. This redox reaction moves e- closer to oxygen so energy is released

each NADH molecule formed during respiration represents

space shuttle being launched into orbit:

H2 and 02 gases are combined, leads to explosive release of heat and light energy, boosting it into orbit. Explosion = release of energy as the electrons of hydrogen "fall" closer to the electronegative oxygen atoms.

EIP #4

EIP #5

isomerase catalyzes the reversible conversion between these 3 carbon sugar isomers. The next enzyme in the reaction uses only glyceraldehyde phosphate (GP) so its removed as fast as it forms. This pulls the equilibrium in that direction, so the net result is 2 molecules of GP.

conversions of 2 pgals to 2 pyruvates each produce

glycolysis starting materials:

glycolysis ending materials:

8 steps of krebs/citric acid cycle

1. Oxaloacetate is combined with Acetyl CoA to form citrate. 2.Citrate is converted to its isomer, isocitrate, because an isomerization takes place (H and OH swap places). 3. Isocitrate is oxidized and NADH is produced. A CO2 molecule is an output as well. 4. Alpha-ketoglutarate reacts with coenzyme A. Another CO2 is released from alpha-ketoglutarate and NAD+ is reduced to NADH. NADH and CO2 are thus products. 5. A phosphate group is transferred to GDP, which forms GTP. GTP is similar to ATP and is sometimes used to create ATP. 6. FAD oxidizes succinate and makes FADH2. 7. A water molecule is added to the substrate, forming malate. 8. The substrate is oxidized, NAD+ is reduced to NADH, and oxaloacetate is regenerated. The cycle begins again.

definition of chemiosmosis (in general)

ATP synthase is... (structure) and how does it spin

ATP synthase is a multisubunit complex with four main parts, each made up of multiple polypeptides. protons move one by one into binding sites on one of these parts (the rotor) causing it to spin and catalyze ATP production.

During respiration, most energy flows in this sequence:

3 reasons that ATP production isn't exact:

1. phosphorylation & redox rxns aren't directly coupled, so NADH causes production of 2.5 to 3.3 ATP and FADH2 causes production of 1.5 to 2 ATP. 2. NADH is impermeable to the inner mitochondrial membrane, so the type of e- shuttle bringing it in affects. if passed to FAD, 2 ATP, but if passed to NAD+, 3 ATP. 3. if the proton-motive force generated by the redox rxns of repiration is used for other things instead of ATP synthase.

Before amino acids can feed into glycolysis or the citric acid cycle...

in oxidative phosphorylation, each member of the ETC is lower in ___ than the preceding member of the chain, but higher in ___. the molecule at zero free energy, which is ___, is lowest of all the molecules in free energy and the highest in electronegativity.

in the energy payoff phase, what happens?

in glycolysis, glucose is turned into:

explain the 4 steps of the transition phase in between glycolysis and the krebs cycle?

1. pyruvate's fully oxidized carboxyl group (-COO-) is removed and given off as CO2 2. the remaining 2 carbon fragment is oxidized, forming acetate (ionized form of acetic acid). An enzyme transfers the extracted e- to NAD+, storing energy in NADH 3. Coenzyme A (CoA) is attached to the acetate, making the acetate very reactive, so this new acetyl CoA has a high potential energy 4. Acetyl CoA breaks and CoA is released while the acetyl enters the cycle.

In the citric acid cycle, how many FADH2 have been formed?

In the citric acid cycle, how many ATP are formed?

transition phase reduces what electron carrier & how much

what happens to the 6 carbon mc's found in the original glucose molecule

they are all eventually released as CO2, since citric acid cycle only wants the electrons. starting with one 3 carbon pyruvate, 1 CO2 is released during transition phase, and 2 CO2 are released during cycle.

each member of the ETC is lower in _______ than the preceding member of the chain, but higher in ___________. The molecule at zero free energy, which is ______ is lowest of all the molecules in free energy and highest in electronegativity.

the two electron carrier mc's that feed electrons into the electron transport system are...

explain how ATP synthase uses the flow of H+ to make ATP:

H+ ions want to get into the cell because of their concentration gradient, so they flow through the stator (half channel in membrane) and bind to active sites on the rotor, changing the shape of each subunit so that the rotor spins. Each H+ ion makes one complete turn before leaving the rotor and passing through a second half channel to enter mitochondrial matrix. Spinning of the rotor turns a rod in the catalytic knob, which is held stationary by the stator. turning of the rod actiates catalytic sites were ADP is bonded, and ATP can be formed.

how does the ETC form the H+ gradient across the mitochondrial membrane?

ETC uses the exergonic flow of e- from NADH and FADH2to pump H+ out across the membrane. H+ then want to get back in because of their concentration gradient, and their only option to get back in is ATP synthase.

in pyruvate decarboxylation (transition phase) and the Krebs cycle, each NADH yields...

FADH2 yields

what is the electron acceptor in fermentation

explain how alcohol fermentation starts with glucose and yields ethanol.

glucose turns to pyruvate, causing 2NADH to be formed. 2ATP are be formed simulaneously from this energy. pyruvate is then turned to 2 aldehydes and releases CO2. Then the acetaldehyde becomes ethanol (anabolic) so it takes e- from NADH to form 2NAD+. This cycle of NAD+ is important so the cell doesn't run out.

glucose turns 2 NAD+ and 2 ADP to 2 NADH and 2 ATP, forming pyruvate. pyruvate is reduced directly by NADH to form lactate without releasing CO2. Lactate is converted back to pyruvate by 2NADH in liver cells after strenuous exercise in animals.

what 3 organic macromolecules are often utilized to make ATP by cellular respiration and how

explain the difference in energy usage between the catabolic reactions of cellular respiration and anabolic pathways of biosynthesis

biosynthetic pathways consume ATP (ex) glucose being made from pyruvate, fatty acids being made from acetyl coa. they're inversely related: metabolic interchanges allow our cells to convert certain molecules to others as we need them. (ex) if we eat more food than we need, we store fat even if our diet is fat-free because of the adaptability of metabolism.

explain how AMP stimulates CR while citrate and ATP inhibit it

Adenosine monophosphate derived from ADP. As ATP accumulates, inhibition of the enzyme slows down glycolysis. when ATP->ADP->AMP faster than ATP is being made, CR is stimulated once again. Also as citrate accumulates, glycolysis slows down because of inhibitors.

explain picture of CR

glycolysis turns glucose to 2 pyruvate, forming 2NADH and 2 net ATP. 2 pyruvate is turned to 2 acetyl coa by 2 NADH in transition phase. In citric acid cycle, 6NADH, 2 FADH2, and 2ATP are formed per glucose. In ETC, NADH or FADH2 from glycolysis or citric acid cycle form about 32 or 34 ATP through chemiosmosis and oxidativ phosphorylation.

chemosynthetic autotrophs:

state the most likely hypothetical order of evolution of anaerobic respiration, aerobic respiration, and photosyn

1st: anaerobic respiration before oxygen existed in the air. Then photosyn released O2 into the air and then CR developed, taking O2 from the air. photosyn & CR came after anaerobic CR since they require organelles, but anaerobic CR doesn't so it occured in ancient prokaryotes.

why do hydrogen atoms accompany electrons as they are transferred to the membrane

positively charged H+ ions can't pass membranes alone, so they accumulate in the two layers of the mitochondria. For the atoms to pass through the membrane, electrons' energy from broken mc's is used to stimulate their transmembrane protein channels.

why do hydrogen atoms accompany electrons as they are transferred through biological systems?

So when they reach the transmembrane proteins in ETC, electrons can stimulate them to let the H+ pass out, forming a gradient that will eventually form ATP.
Also H+ accompany e- as they are transferred in biological systems in order to make water at the end of the process.

why is it thought that glycolysis is the first catabolic pathway to have evolved int he metabolism of all cellular systems

what would happen if anaerobic cellular systems didn't turn to fermentation?

with each breakdown of glucose, 2pyruvate, 2 NADH, and 2 ATP are formed. If all the NAD+ is used up to make NADH though, there's no way to get it back and reuse it so the process must continue to lactate or ethanol+CO2, which turns the NADH to NAD+.

In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in ____.

what is oxidative phosphorylation?

1. Electron transport chain: electron transport and pumping of H+ protons out, which creates an H+ gradient across the membrane. This uses the energy of NADH and FADH2, and indirectly turns 2H+ and O into H2O 2. Chemiosmosis: ATP synthesis powered by the flow of H+ back across the membrane through ATP synthase

explain the 5 steps chemiosmosis (ATP synthesis through ATP synthase)

1. H+ ions flowing down their gradient enter a half channel in the stator, which is anchored in the membrane. 2. H+ ions enter binding sites within a rotor, changing the shape of each subunit so that the rotor spins within the membrane. 3. Each H+ ion makes one complete turn before leaving the rotor and passing through a second half channel in the stator and into the mitochondrial matrix. 4. Spinning of the rotor causes an internal rod to spin as well. This rod extends like a stalk into the knob below it, which is held stationary by part of the stator. 5. Turning of the rod activates catalytic sites in the knob that produce ATP from ADP and Pi.

explain the 8 steps of linear electron flow in photosynthesis, through PS II and then PS I.

1. a photon strikes a pigment molecule in PS II, boosting one of its electrons to a higher energy level. As this electron falls back, it boosts a nearby electron in a nearby pigment molecule, "passing the charge" until it reaches the P680 pair of chlorophyll molecules. The electron then gets transferred to the primary electron receptor. An enzyme catalyzes the splitting of a water molecule into 2e-, 2H+, and one O. the e- replace the electron hole in P680. O combine together & form O2. Each electron then passes from PS II to PS I via electron transport chain. The exergonic fall of e- to a lower energy level provides energy for the synthesis of ATP: As electrons pass through the cytc, the pumping of H+ builds a proton gradient that is used in chemiosmosis. The same process then occurs in PS I with P700 molecules. Then, e- pass down a second electron transport chain but no proton gradient is generated so no ATP is made. Finally the e- are stored in NADPH.